fast-uri vulnerable to path traversal via percent-encoded dot segments
### Impact `fast-uri` v3.1.0 and earlier decodes percent-encoded path separators (`%2F`) and dot segments (`%2E`) before applying dot-segment removal in `normalize()` and `equal()`. This makes encoded path data behave like real `/` and `..`, so distinct URIs collapse onto the same normalized path. For example, `http://example.com/public/%2e%2e/admin` normalizes to `http://example.com/admin`, and `equal()` considers them the same URI. Applications that normalize or compare attacker-controlled URLs to enforce path-based policy can be bypassed. A path that looks confined under an allowed prefix can normalize to a different location. ### Patches Upgrade to `fast-uri` >= 3.1.1, or if you are in the v2.x release line, v2.4.1 ### Workarounds None. Upgrade to the patched version.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-6321US | — | — | ||
fast-uri decoded percent-encoded path separators and dot segments before applying dot-segment removal in its normalize() and equal() functions. Encoded path data was treated like r… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:19238WEB
- https://access.redhat.com/errata/RHSA-2026:20338WEB
- https://access.redhat.com/errata/RHSA-2026:21338WEB
- https://access.redhat.com/errata/RHSA-2026:24473WEB
- https://access.redhat.com/errata/RHSA-2026:24766WEB
- https://access.redhat.com/errata/RHSA-2026:24866WEB
- https://access.redhat.com/errata/RHSA-2026:24977WEB
- https://access.redhat.com/errata/RHSA-2026:25089WEB
Advisories like this name the exposed products attackers go after on your perimeter. See what is exposed on your perimeter with a free passive scan.
Free scan